<h2>My Heroes</h2>
<div>
  <label>Hero name:
    <input #heroName />
  </label>
  <!-- (click) passes input value to add() and then clears the input -->
  <button (click)="add(heroName.value); heroName.value=''">
    add
  </button>
</div>
<ul class="heroes">
  <li *ngFor="let hero of heroes"><!-- 循环数据 -->
    <!--
    [class.selected]="hero == selectedHero"
    (click)="onSelect(hero)">
    -->
    <a routerLink="/detail/{{ hero.id }}">
      <span class="badge">{{ hero.id }}</span> {{ hero.name }}
    </a>
    <button class="delete" title="delete hero" (click)="delete(hero)">x</button>
  </li>
</ul>
<!-- 单向数据绑定HeroesComponent.selectedHero到HeroDetailComponent.hero -->
<!-- <app-hero-detail [hero]="selectedHero"></app-hero-detail> -->
